This was operating before bitcoin and was used successfully by drug dealers for transferring money. This collapsed when measures were taken after 9\11 and also to combat transfer of drug money. I think digital currencies are being used mainly for the same reason, hence, there will be a Crack down by law enforcement agencies. In addition if you are dealing in dirty money do you want volatility whereby you could lose 20 percent value within a day.
My long term pick is XRP since it seems banks will use it instead of swift.
